Silicon-based bipolar power switching devices such as insulated-gate bipolar transistors (IGBTs), bipolar junction transistors (BJTs) or thyristors like gate turn-off thyristors (GTOs) or metal-oxide-semiconductor (MOS) controlled thyristors (MCTs) have high blocking voltages and low direct current (DC) power losses due to conductivity modulation. Silicon (Si) bipolar devices are generally the preferred technology for high voltage high power conversion circuits, which require power switches having blocking voltages of approximately 600 V or higher.
However, the switching losses of Si bipolar power devices are relatively high. The turn-off loss of Si bipolar devices is high since extraction of stored minority carrier charge occurs under high voltage conditions. The turn-on loss can also be substantial due to the time it takes for the entire device thickness to be flooded with minority carriers upon turn-on. Further, high density carrier plasma in such devices is often unstable under the conditions of high electric field due to avalanche multiplication.
Generally, it would be advantageous to prevent excessive switching losses in silicon bipolar devices, as well as to protect them from instability due to simultaneous high-current high-voltage operation.
Thus, there is a need for providing new designs of solid-state devices and circuits, and of controller circuits thereof that would alleviate, or at least mitigate, some of the above-mentioned drawbacks.